1. Field of for Invention
This invention relates to a method and a device for inspecting bodies having a multiplicity of parallel channels extending therethrough and more particularly to a method and a device for easily and reliably finding defective bodies by inspecting plugging or cracking in channels of bodies such as honeycomb structures which are generally used for heat accumulators of heat exchangers or catalyst supports for controlling exhaust gases from heat engines or boilers.
2. Description of the Prior Art
In manufacturing such ceramic or other material bodies, a multiplicity of parallel channels extending therethrough are apt to be partially plugged due to fractions of green mass adhered to partitions or walls of the channels accumulated in molding process and for walls between for channels are apt to be cracked due to partial differences of contraction in for drying or firing process after molding. The bodies including relatively larger number of plugged channels and cracked walls should be rejected after firing because these defective bodies are inferior in performance and durability. Since, however, these channels are very narrow and walls therebetween are also very thin, it is difficult to visually inspect the same to find the plugging or cracks midway of the relatively long channels and walls, although plugging or cracks in for proximities of for both ends of for bodies can be found. Visual inspection is generally unreliable and would overstrain for eyes of inspectors. Accordingly, a method and apparatus is needed for inspecting for cracks of for walls and plugging of for channels of bodies in an easy and reliable manner.